A survey about HOUDRY as a patronym was recently conducted by the authors. The minitel (French electronic phone directory) was used as it references almost of the French people. The results were:
over 50 % of the HOUDRY people are in the department of Seine-et-Marne (see Fig. 2);
the only visible focus is in Brie (see Fig. 2);
two other focuses are notable for OUDRY: one in the department of Deux-Sèvres and the other always in Seine-et-Marne.
Several focuses have been identified:
HOUDRY: departments of Aisne, Aube, Essonne, Ille-et-Villaine, Indre-et-Loire, Marne, Paris, Sarthe, Seine-et-Marne and Val-d'Oise;
OUDRY : departments of Aisne, Aube, Deux-Sèvres, Marne, Saône-et-Loire and Seine-et-Marne (and even in the Val d'Aoste in Italy).
These different groups seem to be generally not linked. But the groups of Brie and Burgundy should be linked towards the XVIth or XVIIth centuries.
In the department of Seine-et-Marne, the main presence of the [H]OUDRY people is today always in the same area than in the past times (between Coulommiers and La Ferté-Gaucher).